Process and apparatus for increasing the production of oil-wells.



. L. DUNN,

'PNocEss ANn APPARATUS EON INCREASING THE PRonucnoN or o|L wELLs.,

Patented Jan. 8,1918.`

APPLICATION FILED MAY I3. l9l6.

i siderable measure of success.

L. DUNN, OF MARIETTA, OHIO, ASSIGNOR T0 PETROLEUM PATENTS COMP,

0F CHICAGO, ILLINOIS, A CORPORATION 0F MAINE.

Specicaton of Letters Patent.

Patented dan, 8, i918.,

Application filed May 13, 1916. Serial No. 97,223.

To aZZ whom 'it may concern: Be it known that I, IRWIN L. DUNN, acitizen of the United States, residing at Marietta, in the county ofWashington and State ofOhio, have invented certain new and usefulImprovements in Processes and Apparatus for Increasing` the Productionof Oil-l/Vells, of which the following is a specication.

Considerable areas of oil territory exlst at the present time which havebeen drilled with numerous oil wells, the production of which has fallenoii to such a point that the operation of the wells is of little profitand in many eases the wells have been abandoned altogether. It has beenproposed to increase the productionof such oil territories by utilizingone of the wells thereon for forcing in to the oil rock a supply ofcompressed air, compressors beingl connected to such well for thispurpose, the other wells being retained rin their usual condition andpumped by the apparatus ordinarily employed for that purpose. Thisprocess has actually been put into extensive use and in the majority ofcases has met with a con- In some localities, however, the air forcedinto the rock instead of penetrating the full depth? and thicknessthereof, and so extracting the oil from the pores of the rock andforcing i it to thepump of the wells finds an easier course through theupper layers of the rock probablybecause such rlayers contain no oil orfollows the more porous open portlons of the sand and escapes from thepumping wells without fully performing its mission. It is one of theObjects of the present 1nventicn to overcome this diiiiculty by forcingthe air to penetrate the lower layers and finer, less perviousportions'of 'the oil sand before it can be released at the pumpingwells. c l

It is a further purpose of the invention to automatically maintain aCpredetermined back pressure upon the oil and air in the rock whichfurther assists in causing the air to penetrate throughout the sand, thedenser and therefore less pervious portions as well as the coarser andmore penetrable portions thereof, whereby the oil is more completelyexhausted.` The advantages of my improvement, however, are notI confinedgreat without the creation of artificial pressure.

The accompanying drawing shows diagrammatically a preferred means forcarrying out my invention, Figure l representing a vertical section ofan oil region equipped with apparatus for practising my invention, andFig.' 2 a modification of one ofthe details' thereof. Referring first toFig. l I have shown therein diagrammatically two wells, both of whichpenetrate through the overlying layers 3 to the oil bearing rock 4, theupper part of` which latter 4 is indicated as devoid of oil, and thelower part 4b containing oil. To the casing 5 of the well, at which theair or other gas under pressure is to be introduced is connected an aircompressor pump' shown diagrammatically y face of the oil thereinindicated at 8. The

space between the casing and tubing is suitably closed or packedpreferably, where the well is a deep well, at or near the junction ofthe overlying rock and oil rock as at 9, though in case-the well is ashallow well the space may be closed at the top by the an- `nularchamber 10 shown in Fig. 2, which may be providedwith a pressure gage11.

The lower endA of the tubing 7 may be simply left open, or perforated asat 12, and within the tubing is arranged the pump tube 13, which may beof any well known or suitable character, though preferably I place theworking barrel 15 thereof at a considerable distance above the bottom ofthe well as shown.

In the drawing for the sake of clearness the tubing 7 is shown as of aconsiderably larger diameter than the pump tube 13,'but ordinarily'thediameter will be much less than shown so that the 'capacity of theannular space between the tubes will be relatively small per linear`foot. The location of the working barrel in the pump with reference tothe bottom of the well varies according to the particular conditions tobe met, and the back pressure which it is desired to maintain. Obviouslythe height of the column of oil in the tubing 7 will depend upon -theworking barrel by reason of which, when the oil has been exhausted tosaid nipple, no

more oil is raised rby the pump until additional supplies have flowedinto the tube 7. Thus there is always a back pressure automaticallymaintained by the column of oil4 in the tube 7, the limits of'whichb'ack pressure are determined by the location of the flood nipple andthe rock pressure. Thus if, for example, the rock pressure amounts toten pounds, 1t is capableof sustaining a column of oil in the wellapproximately twent feet above the oil level inthe rock, and pre erablythe working barrel and the liood nipple are located five or six feetbelow this eight, or fourteen or fifteen feet above the oil level in thewell. The column of oil in the tube 7 therefore varies between fourteenor fifteen feet when the well has just been pumped, and twenty feet whenthe pump as been at rest for some time, andthe back pressure variescorrespondingly. As the oil carries with it into the tube 7, even wherethe level of the oil in the rock is not reduced to that of the lower endof the tube 7, a not inconsiderable quantity of gas, in order to avoidthe accumulation of gas in theupper art of the tube 7, which wouldincrease the ack pressure perhaps to an undesirable extent, openings 16tol the atmosphere are formed in the diaphragm in the u per end of thetube 7 to permit the escape oi) the gas. In some instances 1t has beenfound desirable to subject the oil in the rock to marked'variations inpressure, that is to say, to accumulate a considerable pressure thereinand then suddenly release the pressure at the well. In order to effectthis operation I mount thel working barrel near the bottom of thevpumptube, in which location it will nearly empty the tubing 7- at eachpumping, thus relieving the back pressure or're'ducing it to a verysmall amount.

From the foregoing it will be'seenythat Y the improved process andapparatus is independent of the nature of the rock pressure Whethernatural or artificial, and in either case conserves the rock pressureand insures its action throughout the oil stratum. This is true whetherthe-gas containing rock is in immediate contact with the oil rock, or

as is not unfrequently the case separated therefrom more or less by acomparatively impervious layer. l y

The tube or sleeve 7 prevents the air passing directly through the upperlayers of the nsand to the well and forces it to descend to the lowerlayers to drive the oil therefrom. If ultimately the pressure of the airrises to such a point and the oil is so far exhausted that some of theair enters the openings 12, the rock pressure is still maintained by theweight of the column of oil.

While Iv have shown a single pumping well, it is to be understood that aconsiderable number of such wells may be used in conjunction with asingle air forcing apparatus, or if desired more than a single well maybe employed for the introduction of air. Ordinarily, however, theprocess is applied to a lease or area having a number of oil wells whichhave been bored for operation according to the previous methods, and oneof the, wells is selected for the introduction of air and the otherseither equipped with the construction disclosed, or some of them pluggedto prevent the escape of the pressure air. The equipment of the severalpumping wells will ordinarily be substantially the same, but thelocation of the flood nipple 14 will vary according to the pressurewhich it is desired to maintain upon the particu-larI well to which itis applied. W'here by reason of their different distances from the pointof air supp-ly, or because of peculiarities of geological formation,certain of the wells of th group are inclined to take the air at theexpnse of more remote or less accessible wells, by suitably locating theworking barrels and flood nipples, the relative pressures in the variouswells may be so regulated that the air will be distributed evenly amongthem.. 1

It is sometimes desirable and is practicable to introduce the pressureair or gas into the rock through one of the pumping wells. This may beaccomplished in the Well shown in Fig. 2 of the drawing by connecting upto the nipple '1 7 a compressor or other source of gas under pressure.The gas introduced at the' nipple 17 flows downwardly between the casing5 and tubing"7 through the open lower end of the former and venterstheroil rock where it is diffused in the upper part of the rock andserves to increase the pneu- Amatic'pressure therein. v

I claim: j

1. A process of operating oil wells which consists -in introducingcompressedgas to the oil sand in which the wells are located,maintaining a column of oil in the well to be pumped to exert a backpressure upon the compressed gas, and pumping the oil from said wells. v

2. Apparatusfor producing oil comprising means forintroducing compressedgas means? into the oil sand, a well casing, a tubular member in saidwell casing, packed with respect thereto, and extending below the levelof oil in the rock, and means for pumping the oil from said tubing. Y

3. Means for producing oil from oil-bearing rock, comprising means forforcing compressed gas into said rock, a well having a casing, a tubeWithin the casing extending down into the oil sand' below the oil levelltherein, means for preventing the escape of gas between thercasing andthe tubing, and an oil pump in the tubing, the Working barrel of whichis located a substantial distance above the oil level in the sand.

4. Means for producing oil from oil-bearing rock,\comprising means forforcing 'compressed gas into said rock, a well having a casing, a tubeWithin the casing extending down into the oil sand below the oil leveltherein, means for preventing the escape of gas between the casing andthe tubing, and an oil pum in the tubing, the working barrel of whlch islocated a substantial distance above the oil level in the sand, and aHood nipple located below the Working bar- A rel in the pump.

5. Apparatus for producing oil comprisy ing a well casing, a tubularmember in said v well/casing but spaced therefrom and eX- tendindownwardly beneath the surface of the oil 1n the oil rock and an oilpump within the tubular member, the working barrel of which pump islocated a substantial dis-l tance above the oil in the rock.

- IRWIN L. DUNN.

